Three-dimensional measurement method of laser welding temperature field

Abstract

The invention relates to a laser welding temperature field 3D measurement method, which comprises the following steps: subjecting grey level images of a melting zone and heat affected zone thereof on the upper and the lower surfaces during welding to temperature calibration of each zone by using the grey level images of a melting zone and a heat affected zone thereof; extracting the dividing contour line of the melting zone, the heat affected zone and a mother material zone; locating the positions of small holes on the upper and the lower surfaces in the welding zone to obtain the axial positions of the small holes inside a welding part, and reconstructing the 3D dividing contour surface of the melting zone, the heat affected zone and the mother material zone; and obtaining the temperature field distribution and the 3D distribution data of temperature fields of the melting zone and the heat affected zone at arbitrary thickness, and constructing a continuous dynamic change models of the temperature fields of the melting zone and the heat affected zone.

Description

technical field [0001] The invention relates to a three-dimensional measurement method for a laser welding temperature field, which belongs to the technical field of measurement. Background technique [0002] Due to the fast heat propagation speed in metal materials, the heat source density is highly concentrated during laser welding, so the temperature field during welding is very uneven, especially due to the existence of high-temperature metal vapor / plasma, liquid molten pool, solid heat-affected zone and In the solidification cooling area, even for the welding of the same material, the temperature difference in these areas is very large, such as the temperature of metal vapor / plasma can be as high as 8000 ° C, while the temperature of the solidification area may be several hundred degrees, and the melting point of the material to be welded There is a big difference, for example, the melting point of aluminum alloy is about 600°C, while that of titanium alloy is about 170...

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Problems solved by technology

Steen superimposed the point heat source of the orifice plasma and the small hole line heat source, and developed the mathematical model of the point and line heat source, which is in line with the actual welding situation, but it cannot get satisfactory results for finite thick parts

It is difficult to obtain accurate data for all these simulation studies, and because the temperature field not only directly passes thermal strain during welding, but also indirectly determines the welding residual stress through the phase transformation and strain caused by the change of metal state and microstructure, so it is accurate The temperature field measurement technology plays an important role in the prediction of welded structures

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